Electric heating and air circulating unit



G. J. CAMPBELL ELECTRIC HEATING AND AIR CIRCULATING UNIT Nov. 15, 1955 a H m m m M/ M m m Filed May 29, 1955 Nov. 15, 1955 G. J. CAMPBELL. 2,724,044

ELECTRIC HEATING AND AIR CIRCULATING UNIT Filed May 29, 1955 2 Sheets-Sheet 2 IN V EN TOR.

Unite States Patet' fiice 2,724,044 Patented Nov. 15, 1955 ELECTRIC HEATING AlilD AIR. CIRCULATING UN '1 Gregory J. Campbell, Freeport, 11L, assignor to St. Joe Machines, Inc., St. Joseph, Mich.

Application May 29, 1953, Serial No. 358,427

11 Claims. (Cl. 219-39) This invention relates to improvements in electric heating and air circulating unit.

The principal objects of this invention are:

First, to provide an inexpensive electric heating and air circulating unit that can be installed between the studding of a wall and thereafter serviced as necessary through air intake and discharge openings and switch box projectingto the surface of the wall.

Second, to provide a novel air heating and circulating unit in which the electric heating element will not operate unless the circulating fan is also operating.

Third, to provide novel means for removably supporting an electrical heating element and an air circulating fan within a conduit mounted within the, wall of a room.

Further, to provide a novel control circuit including a novel fusing arrangement which permits an electric heating element to be mounted within an enclosed duct in a wall and independently energized with respect to an air circulating blower without danger of the heating element becoming overheated due to failure of the blower.

Other objects and advantages of the invention will be apparent from a consideration of the following description and claims. The drawings of which there are two sheets illustrate a highlypractical form of the invention.

Fig. 1 is a fragmentary perspective view of a portion of a room and wall with the heating unit installed therein.

Fig. 2 is a fragmentary front elevational view of the heating unit partially broken away in vertical cross section;

Fig. 3 is a fragmentary vertical cross sectional view through the heating unit.

Fig. 4 is a schematic wiring diagram of the connections between the electrical elements of the unit.

Fig. 5 is a perspective view of the heating element incorporated in the unit.

Fig. 6 is an enlarged fragmentary cross sectional view through the heating element and its enclosing column and taken along the plane of the line 6-6 in Fig. 5.

Fig. 7 is a fragmentary perspective view of the lower end of the heating unit with an air directing and heating element supporting baffie partially installed therein.

Fig. 8 is a fragmentary cross sectional view through novel fuses employed in the electrical circuit of the unit.

As is indicated in the objects of the invention, the heating unit is adapted to be built into the wall of a room but may be positioned against the wall and projecting into the room if desired. The unit is adapted as will be described to circulate air in the room either with or without the addition of heat to the circulated air. In the drawings the reference numeral 1 indicates the wall of a room. 2 represents the innersurface of a double wall construction spaced rearwardly or outwardly from the inner surface of the wall 1. The heating unit comprises generally an upright tubular column 3 of rectangular cross section adapted to fit within the hollow wall between the wall surface 1 and 2. The column is closed at its ends by end walls 4. The front wall 5 of the column has a forwardly opening inlet port 6 formed therein near its upper end and a forwardly opening discharge port 7 formed in its lower end. Opening 8 is formed in the front wall of the column intermediate of its ends to receive a junction box 9. A blower unit indicated generally at 10 is mounted within the upper end of the column while a heating element 11 is mounted within the lower end of the column above the discharge port 7. A manually controllable switch 12 and a thermostat 13 are mounted on the junction box 9.

An upper throat 14 of rectangular outline has a rear wall 15 that is secured to the front wall of the column and around the inlet port 6 as by screws 16. The rear wall 15 has a rearwardly turned venturi 17 formed thereon and opening into the column. An upper grill 18 is provided with a peripheral flange 19 adapted to fit around and be secured to the throat 14.

The rear wall 15 of the mounting plate has forwardly projecting pins or screws 20 thereon supporting a spider 21 across the front of the venturi 17. Suitable rubber grommets are provided at 22 to yieldingly support the spider. The spider 21 in turn supports an electric motor 23 that projects into the venturi 17 and the upper end of the column. A rotor 24 is secured to the inner end of the shaft of the motor and partially embraces the motor. A spirally disposed baflle plate 25 is positioned in the upper end of the column to form a downwardly facing discharge throat 26 positioned along one side of the column.

The heating element comprises a tubular box like carrier 27 having downwardly tapering end walls 28 and downwardly converging front and back walls 29. Secured to the walls 29 as by bolts 3% are insulating supports 31 for the electrical heating coils 321. The lower edges of the walls 29 are turned forwardly and backwardly in locating flanges 32 and the rear locating flange 32 is provided with downwardly extending ears or lugs 33. The carrier 27 is supported within the column by engagement of the lugs 33 in slits 34 formed in the top horizontal flange of a downwardly and forwardly curved baffle plate 35. With particular reference to Fig. 7, it will be noted that the carrier 27 with its heating elements attached may be forced upwardly in the bottom of the column and the baffle plate 35 thereafter installed until the lugs 33 engage in the slits 34 with the lower curved end of the baflie positioned in the discharge throat 7. The lower grill 181 may then be engaged over the forwardly projecting discharge throat 7. The lower end of the baffle 35 is flanged downwardly and rearwardly to engage under a spring clip 36. The switch box 9 is provided with a laterally extending feed conduit 37 and is conected to upwardly extending conduit 38 and downwardly extending conduit 39. The upper edges of the side walls 29 of the carrier are sloped downwardly and outwardly and are notched as at 40 to space the upper end of the carrier from the walls of the column and permit the circulation of air around the outer sides of the carrier and prevent overheating of the column walls. The downwardly converging position of the two electrical heating elements 31 causes the air to move between converging heating elements for eificient heat transfer.

The circuit for connecting the elements of the heating unit is illustrated in Fig. 4. The conductor 42 forms the grounded side of a 110 volt circuit or the neutral line of a 220 volt 3 wire circuit. When the heating unit is connected for 110 volt operation the current is directed through the fuse 43 and conductor 44 to a thermostat 13. From the thermostat 13 the current is directed to the movable pole 46 of the switch 12 and can be connected through the conductor 47 to the motor 23. Conductor 48 returns the circuit directly to conductor 42. Simultaneously the switch 46 closes on conductor 49 that is connected to one end of a heating coil 50A. The coil 50A is connected in parallel with a second coil 508 by connec tion of jumpers 51 and 52 that are installed for volt operation. Current is returned through the jumper 52 to 3 the conductor 42. For operation of the motor 23 without the heating elements 50A and 50B the switch 46 is closed on the terminals 53 to connect the thermostat bridging conductor 54 to the motor.

For 220 volt operation, the jumpers 51 and 52 are removed or disconnected and 110 volt current may be supplied to the motor 23 from the conductor 44 as previously. 220 volt current is supplied through the conductor 55 to the heating element 503 and in series through the element 50A to conductor 49 for return through the switch 46 and thermostat 45. As with the 110 volt circuit the fan can be operated without the heating elements.

In order to protect the heating unit as described above against over heating, the fuse 43 is of special construction and location. As is best illustrated in Figs. 2 and 8, the fuse consists of an insulating base plate 56 secured to the motor support plate and provided with a rearward extension 57 projecting into the discharge throat 26 of the blower. An insulating bar 58 is removably secured to the base 56 by nuts 59 and is provided with a rearward extension 60 projecting through the extension 57. The extension 60 is vertically grooved as at 61 and a thin strip of low melting point fuse metal 62 is wrapped along the sides of the projection 69 and over the groove 61 so as to be fully exposed to the air stream in the throat 26. Terminal plates 63 make contact at the ends of strip 62 for connecting it in series with the previously described conductor 44. The heating elements 50A and 503 combine to create a relatively large load which may be in the neighborhood of 11 amperes. The portion of the fuse strip 62 which bridges the groove 61 is cut or trimmed to have an electrical carrying capacity substantially less than the over load of the heating elements. For example, the fuse may be rated at about 6 amperes when the load is rated at 11 amperes. The fuse strip 62 would automati' cally burn out or melt if operated under these conditions for a short period of time. However, the location of the fuse strip in the air stream from the blower causes the heat created in the fuse strip to be dissipated before the fuse strip can melt. Should the motor stop for any reason, the air stream is, of course, interrupted and the fuse strip rapidly heats and melts to disconnect the heating elements 50A and 508.

Having thus described my invention, what I claim to be new and desire to secure by Letters Patent is:

1. An electric heating and air circulating unit adapted to be installed within the wall of a room comprising, a tubular column of rectangular cross section closed at its upper and lower ends and having inlet and outlet ports formed respectively in the top and bottom of its front wall, removable grilles covering said ports, a spider removably secured to said front wall and bridging said inlet port, a motor carried by said spider, a blower rotor mounted on the inner end of the shaft of said motor, a blower casing enclosing said rotor and having a discharge end directed downwardly along one edge of said column, a rectangular tubular carrier fitted within the lower end of said column and having converging front and back side walls, electric heating elements supported on the insides of said walls in downwardly converging spaced relation, outturned spacing flanges on the upper and lower edges of said carrier walls and spacing said carrier from the sides of said column while permitting air flow along the outer sides of the carrier, lugs turned downwardly from the spacing fiange on the bottom and rear side of said carrier, a downwardly and forwardly curved air directing baffie in the bottom of said column, said baffie extending upwardly at its rear edge above said outlet port and being removable through said outlet port, said lugs being supported by the upper edge of said bafiie, a switch box and switch carried on the front side of said column, wiring connecting said motor and said heating elements in parallel to said switch, and a fusible link connected in series with said heating elements, said link having a portion disposed in the air stream issuing from said blower casing ahead of said heating elements, the exposed portion of said link having a lower electrical capacity in still air than the rated capacity of said heating elements.

2. An electric heating and air circulating unit adapted to be installed along the wall of a room comprising, a tubular column closed at its upper and lower ends and having inlet and outlet ports formed respectively in the top and bottom of its front wall, removable grilles covering said ports, a spider removably secured to said front wall and bridging said inlet port, a motor carried by said spider, a blower rotor mounted on the inner end of the shaft of said motor, an air directing panel embracing said rotor and having a discharge directing end directed downwardly within said column, a tubular carrier fitted within the lower end of said column and having downwardly converging opposed Walls, electric heating elements supported in downwardly converging spaced relation on the insides of said walls of said carrier, outturned spacing flanges on the walls of said carrier and spacing said carrier from the sides of said column while permitting air fiow along the outer sides of the carrier, lugs projecting from the bottom and rear side of said carrier, a down- Wardly and forwardly curved air directing bafile in the bottom of said column, said bafiie extending upwardly at its rear edge above said outlet port and being removable through said outlet port, said lugs being engaged with and supported by the upper end of said bafile, a switch box and switch carried on the side of said column, wiring connecting said motor and said heating element in parallel to said switch, and a fusible link connected in series with said heating elements, said link having a portion disposed in the air stream issuing from said blower ahead of said heating elements, the exposed portion of said link having a lower electrical capacity in still air than the rated capacity of said heating elements.

3. An electric heating and air circulating unit adapted to be installed along the wall of a room comprising, a tubular column closed at its upper and lower ends and having inlet and outlet ports formed respectively in the top and bottom of its front wall, removable grilles covering said ports, a spider removably secured to said front wall and bridging said inlet port, a motor carried by said spider, a blower rotor mounted on the inner end of the shaft of said motor, an air directing panel embracing said rotor and having a discharge directing end directed downwardly within said column, a tubular carrier fitted within the lower end of said column and having downwardly converging opposed walls, electric heating elements supported in downwardly converging spaced relation on the insides of said walls of said carrier, outturned spacing flanges on the Walls of said carrier and spacing said carrier from the sides of said column while permitting air fiow along the outer sides of the carrier, a switch box and switch carried on the side of said column, wiring connecting said motor and said heating element inparallel to said switch and a fusible link connected in series with said heating elements, said link having a portion disposed in the air stream issuing from said blower, the exposed portion of said link having a lower electrical capacity in still air than the rated capacity of said heating elements.

4. An electric heating and air circulating unit adapted to be installed within the wall of a room comprising, a tubular column of rectangular cross section closed at its upper and lower ends and having inlet and outlet ports formed respectively in the top and bottom of its front wall, a spider removably secured to said front wall and bridging said inlet port, a motor carried by said spider and projecting axially into the top of said column, a blower rotor mounted on the inner end of the shaft of said motor and partially embracing said motor, an air directing panel embracing said rotor and having a discharge directing end directed downwardly within said column, a rectangular tubular carrier fitted within the lower end of said column and having downwardly converging front and back side walls, electric heating elements supported on the insides of said walls of said carrier, outturned spacing flanges on the upper and lower edges of said walls and spacing said carrier from the sides of said column while permitting air flow along the outer sides of the carrier, lugs turned downwardly from the spacing flange on the rear side of said carrier, a downwardly and forwardly curved air directing bafiie in the bottom of said column, said bafiie extending upwardly at its rear edge above said outlet port and being removable through said outlet port, said lugs being engaged with and supported by the upper end of said bafile, a switch box and switch carried on the front side of said column, and wiring connecting said motor and said heating element in parallel to said switch.

5. An electric heating and air circulating unit adapted to be installed within a room comprising, a tubular column closed at its upper and lower ends and having inlet and outlet ports formed respectively in the top and bottom of its front wall, removable grilles covering said ports, a spider removably secured to said front wall and bridging said inlet port, a motor carried by said spider, a blower rotor mounted on the shaft of said motor, an air directing panel embracing said rotor and having a discharge directing and directed downwardly within said column, a rectangular carrier fitted within the lower end of said column and having downwardly converging walls, electric heating elements supported on the insides of said walls of said carrier, outturned spacing flanges spacing said carrier from the sides of said column while permitting air flow along the outer sides of the carrier, lugs on the rear side of said carrier, a downwardly and forwardly curved air directing baflle in the bottom of said column, said baflie extending upwardly at its rear edge above said outlet port and being removable through said outlet port, said lugs being engaged with and supported by the upper end of said bafile, a switch box and switch carried on the front side of said column, and wiring connecting said motor and said heating element in parallel to said switch.

6. An electric heating and air circulating unit adapted to be installed within the wall of a room comprising, a tubular column of rectangular cross section closed at its upper and lower ends and having inlet and outlet ports formed respectively in the top and bottom of its front wall, removable grilles covering said ports, a spider removably secured to said column and bridging said inlet port, a motor carried by said spider, a blower connected to said motor and having a discharge end directed downwardly within said column, a carrier fitted within the lower end of said column, electric heating elements supported on said carrier, spacing members on the upper and lower edges of said carrier and spacing said carrier from the sides of said column while permitting air flow along the outer sides of the carrier, lugs turned downwardly from the spacing member on the rear side of said carrier, a support in the bottom of said column, said support being removable through said outlet port, said lugs being supported by the upper end of said support, a switch box and switch carried on the front side of said column, and wiring connecting said motor and said heating element in parallel to said switch.

7. An electric heating and air circulating unit adapted to be installed along the wall of a room comprising, a tubular column closed at its upper and lower ends and having inlet and outlet ports formed respectively in the top and bottom of its front wall, removable grilles covering said ports, a spider removably secured to said column and projecting over said inlet port, a motor carried by said spider, a blower mounted on said motor and directed downwardly within said column, a tubular carrier fitted within the lower end of said column, an electric heating element supported on said carrier, a support in the bottom of said column, said support being removable through said outlet port, said carrier being engaged with and supported by said support, a switch box and switch carried on the front side of said column, wiring within said column connecting said motor and said heating element to said switch, and a fusible link connected in series with said heating element, said link having a portion disposed in the air stream issuing from said blower ahead of said heating element, the exposed portion of said link having a lower electrical capacity in still air than the rated capacity of said heating element.

8. An electric heating and air circulating unit adapted to be installed along the wall of a room comprising, a tubular column closed at its upper and lower ends and having inlet and outlet ports formed respectively in the top and bottom of its front wall, removable grilles covering said ports, a spider removably secured to said column and projecting over said inlet port, a motor carried by said spider, a blower mounted on said motor and directed downwardly within said column, a tubular carrier fitted Within the lower end of said column, an electric heating element supported on said carrier, a support in the bottom of said column, said support being removable through said lower port, said carrier being engaged with and supported by said support, a switch box and switch carried on the front side of said column and, wiring within said column connecting said motor and said heating element to said switch.

9. An electric heating and air circulating unit comprising, a tubular column, a blower mounted to circulate air through said column, a motor connected to drive said blower, an electric heating element positioned in said column, wiring connected to energize said motor and said heating element, and a fusible link connected in series with said heating element, said link having a portion disposed in the air stream issuing from said blower ahead of said heating eelment, the exposed portion of said link having a lower electrical capacity in still air than the rated capacity of said heating element.

10. An air heating and circulating unit adapted to be installed within the wall of a room comprising a tubular column of rectangular cross section and having inlet and outlet openings formed in its ends, a box-like carrier of rectangular cross section disposed in said column, said carrier being open at its ends axially of said column and having opposite walls converging, projections on said carrier spacing the Walls of the carrier from the walls of the column and permitting air flow around said carrier, electric heating elements mounted in converging relationship on the inside of the converging walls of said carrier, and a blower positioned to circulate air through said column and carrier in a direction to enter said carrier between the wider spaced ends of said heating elements and in contact with the elements.

11. An air heating and circulating unit adapted to be installed Within the Wall of a room comprising a tubular column of rectangular cross section and having inlet and outlet openings formed in its ends, a box-like carrier of rectangular cross section disposed in said column, said carrier being open at its ends axially of said column and having opposite walls converging, projections spacing the walls of the carrier from the walls of the column and permitting air flow around said carrier, electric heating elements mounted in converging relationship on the inside of the converging walls of said carrier, and a blower positioned to circulate air through said column and carrier in a direction to enter said carrier between the wider spaced ends of said heating element and in contact with the elements.

References Cited in the file of this patent UNITED STATES PATENTS 1,961,772 Martin June 5, 1934 2,337,518 Young et al Dec. 21, 1943 2,459,986 Worden Jan. 25, 1949 2,471,784 Seifner et al May 31, 1949 2,528,650 Graham Nov. 7, 1950 

